I think you are incorrect. The 84A has no internal oscilator. It is speced to 10MHz only if you use an extrernal oscilator (not RC curcuit). The max you can get out of an RC curcuit is 4MHz.

I think you might be right on the external oscillator, I usually use the 16f627 or 16f628 for no particular reason other than the first books i had used them, though you could sub one of those to cut down on component count (or rather, other people building the circuit).

I believe there are two different versions of the 16f84a, a 4mhz and 20mhz.

I was thinking of trying something along these lines this weekend for my 8" lilli.

But then I had another thought. Can the monitor's status (on/off) be determined by DDC? I'm wondering, if it's possible, maybe I'll just use a PIC to operate the monitor by IR remote.

Having the PIC determine if the LCD is on or off is a good idea. As it is, I have the PIC code go into a waiting loop for 5-7 seconds while it waits for the LCD to turn on. That is because I have the PIC powered off the car-on but the monitor comes on when the computer powers up. Any signals sent to the LCD before it is on is obvioulsy not going to cause anything to happen. Of course, that could probably be removed now that the PIC can detect what state (VGA v.s. non VGA) the LCD is in. When it couldn't detect state that was much more important because any signal it sent to the LCD was assumed to change the LCDs state. I guess the next time I have the LCD out I'll change that bit of code in the PIC. But I haven't had to touch my setup for many months. It works perfectly except that (because of the delay loop) it won't switch to backup camera the moment the monitor turns on if I am already in reverse [which is usally the case when I am backing out of a parking spot.]. Its a small thing though.